19491998 has 4 divisors (see below), whose sum is σ = 29238000. Its totient is φ = 9745998.

The previous prime is 19491977. The next prime is 19492003. The reversal of 19491998 is 89919491.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4872998 + ... + 4873001.

It is an arithmetic number, because the mean of its divisors is an integer number (7309500).

Almost surely, 2^19491998 is an apocalyptic number.

19491998 is a deficient number, since it is larger than the sum of its proper divisors (9746002).

19491998 is an equidigital number, since it uses as much as digits as its factorization.

19491998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9746001.

The product of its digits is 209952, while the sum is 50.

The square root of 19491998 is about 4414.9742921109. The cubic root of 19491998 is about 269.1238080736.

The spelling of 19491998 in words is "nineteen million, four hundred ninety-one thousand, nine hundred ninety-eight".